The invention relates generally to brachytherapy needles and more particularly to systems that can simultaneously dispense medication along with radioactive seeds.
Brachytherapy refers to a localized method of treating cancer that places radioactive sources directly within tissue. The advantage of brachytherapy is that very high doses of ionizing radiation are delivered to a localized area, such that the radiation is supplied primarily to the treatment area, without significantly affecting tissues throughout the body. This ability, when combined with a rapid reduction in the radiation dose as a function of distance, shields distant anatomies from unwanted radiation. Hence, the technique has provided excellent results for localized control of various tumors.
Brachytherapy commonly employs a method whereby radioactive seeds and optionally spacers, can be implanted in a designated area to treat conditions such as cancer. To treat prostate cancer, needles are inserted through the perineum into the prostate gland. Appropriate needle placement can be determined based on a dosimetry plan prepared by a physician and is commonly executed using a guiding template or grid to guide needle placement as described generally in U.S. Pat. No. 5,931,786 to Witmore, the contents of which are incorporated herein by reference. Additional details are provided in “Ultrasound Guided—Transperineal Implantation for the Treatment of Early Stage Prostate Cancer” by Grimm, Blasko and Nagle in Atlas of Urologic Clinics of North America, Vol. II, No. 2, October 1994, the contents of which are incorporated by reference.
Placement techniques of brachytherapy seeds vary, but generally, they are placed using needles containing both radioactive seeds and optionally spacers, which position the seeds and spacers in accordance with the dosimetry plan. Seeds, and sometimes seeds and spacers, are loaded into the needle cannula and the needle is inserted through the grid into the prostate gland. After the needle is properly positioned in the prostate, a stylet, having a diameter smaller than that of the needle, can be inserted into the needle behind the seeds and spacers. The needle can then be withdrawn over the stylet, which remains fixed in place. In this way, the seeds and spacers are constrained to remain in the prostate as the needle is withdrawn. This is repeated twenty to thirty times to implant a three-dimensional array of radioactive seeds. It is the intention of the physician that the seeds be positioned as precisely as possible to correspond to the three-dimensional dosimetry plan.
The use of twenty to thirty needles breaking through the skin and tissue and leaving behind foreign objects can lead to adverse reactions and trauma to the surrounding area. Trauma, bleeding and swelling to the prostate and surrounding tissue during and after a brachytherapy implant procedure can displace the seeds and lead to imprecise doses of radiation. This can involve some zones that are unintentionally, undesirably, and possibly dangerously, too hot and/or too cold.
Trauma and swelling are commonly treated by administering systemic drugs to the patient. This has the disadvantage of requiring enough drug to be dispersed throughout the body, even though the trauma and swelling are localized. This can delay the effectiveness of the drugs and can cause undesirable drug interactions and might not be suitable for all patients.
Additional known devices used to deliver seeds are disclosed in U.S. Pat. No. 4,402,308 to Scott, U.S. Pat. No. 4,697,575 to Horowitz, U.S. Pat. No. 5,860,909 to Mick, et al. and U.S. Pat. No. 5,938,583 to Grimm, which are incorporated herein by reference. Conventional devices used for storing and delivering radioactive seeds are also described in U.S. Pat. No. 4,086,914 to Moore and U.S. Pat. No. 4,167,179 to Kirsch, which are incorporated herein by reference. However, none of these references adequately disclose methods of treating and addressing the trauma and swelling that can occur at the implantation site.
Accordingly, a need exists for improved treatment of trauma and swelling to tissue caused by a brachytherapy needle implant procedure.